Luxembourg fortress, the Gibraltar of the North and what's left of it

Nearly everything you’ll see in Luxembourg’s old town has to do with a fortress that no longer exists as such. The walls above the Grund, the galleries in the Bock, the towers in the Pfaffenthal and even the squares are remains or traces of one of Europe’s largest fortified sites. Here’s the short version of its story and where to see it today.

A thousand years of building on a rock

UNESCO sums up the beginning in a sentence. At first the city was just a small castle, built shortly after the middle of the 10th century on an almost inaccessible rock. That’s the Bock, which Sigefroi acquired in 963. In the 12th century the settlement that grew beside it was protected by a stone wall, extended in the 14th and 15th centuries.

Sieges set the rhythm. The city tourist office notes that the town rarely fell to a siege before 1443, when Philip the Good, Duke of Burgundy, took it by surprise, and that the French capture of 1684 came at the end of a memorable siege led by Vauban himself. So in 1443 Burgundian troops took it, and through inheritance it passed to the Habsburgs and Spain until 1684. During that period, according to UNESCO, the site became a true fortress. Louis XIV captured it in 1684 and his engineer Vauban extended and reinforced it. In the 18th century the Austrians carried on his work and created the so-called Gibraltar of the North. After the Congress of Vienna, the Prussians, who garrisoned it, added new military structures.

1867, the year it was condemned

The crisis of 1867, with Napoleon III trying to buy the country, ended with the Treaty of London of 11 May. The Prussian garrison left, Luxembourg was declared perpetually neutral and the fortress was to be dismantled. Most of the fortifications came down, but UNESCO notes that many remains from every era survive, among them gates, forts, bastions, redoubts and casemates.

That’s the part I find most interesting. Without the demolition there’d be no Corniche, since the view over the Grund only opened up when the battlements fell, and no municipal park, which was laid out on land the fortress left free. Today’s city is, to a large extent, what was built on its ruins.

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What still stands?

The most impressive part is underground. The Bock Casemates are just one stretch of the 23 km of passages hollowed out of the rock. Above them run the 17th-century ramparts of the Chemin de la Corniche, and across the valley rise the restored towers of the Rham plateau, part of the Wenceslas wall.

Some stand-alone pieces deserve a stop. The Three Towers gate on boulevard Victor Thorn has a square tower from around 1200 flanked by two round ones from the 14th century. In the Pfaffenthal stand the Vauban towers, which closed off the Alzette valley. And on Kirchberg, Fort Thüngen keeps its keep with three round towers crowned by golden stone acorns, which give the Dräi Eechelen museum its name.

Lambert Redoubt and the Grünewald forts

Two pieces hardly anyone looks for, and I would. The Lambert Redoubt, from 1685, belonged to the fort of the same name on the open plain to the west. It was a two-storey pentagon ringed by casemates, flattened in the demolitions of 1868 to 1874, and its remains came to light when the Monterey underground car park was dug, beside the municipal park.

Across the Alzette, on the Grünewald heights, the Dräi Eechelen museum documents the Kirchberg forts. Vauban set his gun batteries at Niedergrünewald during the 1684 attack, then turned it into a crownwork with three bastions and 56 mine chambers; its partly rebuilt keep can be visited from the Vauban walk. Obergrünewald was the old Parc hornwork, renamed by the Austrians in 1716, and a gallery cut through the rock linked it to Fort Thüngen.

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Two walks to explore it on foot

There are two official routes, each with its own page on visitluxembourg and the government’s portal, which I’d do before any paid visit. The Wenzel walk follows the medieval wall of Wenceslas II, from the Bock along the Corniche to the Grund and the Rham plateau, and packs 1,000 years of history into 2.5 km and about three hours, according to the government’s portal. The Vauban circuit is longer, 5.16 km in three hours, taking in the Pfaffenthal and the Grünewald forts, with panoramic views over the upper town.

If you only do one, I’d choose the Wenzel, shorter and with the Corniche included. I’d keep the Vauban for a second day or for anyone who enjoys a climb.

Where does it all make sense?

At the Dräi Eechelen museum. It sits inside the keep of Fort Thüngen, covers 1443 to 1903 through around 600 objects, and a ticket is €7, or €12 if you pair it with the Nationalmusée. It shuts on Mondays and stays open later on Wednesdays. It’s what I’d do on a rainy day, and what I’d suggest before the walks if you’re travelling with teenagers, so they know what they’re looking at afterwards.

All of this heritage is why the old town and its fortifications have been World Heritage since 1994, under UNESCO’s criterion iv, which recognises the role the city played in European history over several centuries.

One last suggestion. If you’d like to see the fortress from a distance before walking it, stand on the edge of Fort Obergrünewald on Kirchberg, where visitluxembourg notes the panoramic view over the upper town and the Bock with its broken gun ports.

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